Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
As a technique to which a typical stepper motor is applied, for example, there is proposed an automatic document feeding device that includes a paper sheet feeder, a conveying unit, a drive transmission unit, a stepper motor, and a control unit. The paper sheet feeder feeds sheets of original documents one by one. The conveying unit conveys the fed original document to an exposure position of a copier. The drive transmission unit transmits a driving power to the conveying unit. The stepper motor provides the drive transmission unit with the driving power. The control unit drives the stepper motor by the number of pulses corresponding to a backlash from this stepper motor to the conveying unit and the number of the pulses required for a phase matching of the stepper motor before a conveyance of the original document.
There is proposed a driving device for switching position that switches at least two positions as another example. The driving device for switching position includes: a stepper motor; a drive shaft driven by the stepper motor; a turning member locked by this drive shaft to integrally turn; a return member turnably located to engage with the turning member; and a bias spring that biases the return member, and configures a longer period until the turning member engages with the return member than an acceleration period at the time point at which the stepper motor starts.